Every time you present information that came from another source, you should create a citation within the text of your paper that includes both the author's last name and the four digit year of publication. You can do this in one of two ways:
Option 1: Mention the author's last name in the sentence where you are presenting his or her findings, followed by the year in parentheses.
Smith (1995) has found evidence that suggests the earth will cool over time.
Option 2: At the end of the sentence, include both the author's last name and year of publication in parentheses, separated by a comma.
Evidence has been found that suggests the earth will cool over time (Smith, 1995).
When including direct quotes from an author, follow the above rules for in-text citations, but with these two additions:
1. Place quotation marks around the direct quote.
2. Include the page number where the quote is found.
"Data indicates that the earth will cool over time." (Smith, 1995, p. 24).
Smith (1995) states, "Data indicates that the earth will cool over time." (p. 24).
When making in-text citations for works that have multiple authors, follow these guidelines:
Two authors: Include the last names of both authors either in the sentence or in parentheses.
Brown and Matthews (1984) have suggested that the earth will warm over time.
It has been suggested that the earth will warm over time (Brown and Matthews, 1984).
Three to five authors: Include the last name of each author the first time the source is cited in your paper. For each in-text citation of the source after that, list only the last name of the first author followed by et al.
(First citation of source) It has been suggested that the earth will warm over time (Brown, Matthews, and Wilson, 1984).
(Later citation of same source) It has been recommended that drastic action be taken to reduce man's influence on the rise of global temperatures (Brown et al., 1984).
Six authors or more: For every in-text citation of the publication, list the name of the first author followed by et al.
It has been suggested that the earth's temperature will generally stay the same over time (Barnes et al., 2007).